Diversity and Distribution of Macrophytes in a Freshwater Wetland, Loboi Swamp (Rift Valley) Kenya

An inventory of Loboi swamp was undertaken to determine the macrophyte diversity and distribution. A total of 36 vascular plant species in 13 families were recorded, with Cyperaceae forming over 30 of macrophytes. Two vegetation zones were observed, characterised by the presence of Typha and papyrus. The Typha zone, comprising over 70 of the swamp, is dominated by T. domingensis and is species rich with 35 plant species whereas the papyrus zone includes the dominant Cyperus papyrus and only one other macrophyte species. Distribution of macrophytes is correlated with depth and period under water, with the Typha zone seasonally flooded while the papyrus zone is permanently under water at depths over 0.5m. Water chemistry has little influence on the distribution of macrophytes in the swamp, but at the edges there is predominance of Cyperus laevigatus in high alkalinity soils. Current uses of the swamp include dry season grazing, harvesting of papyrus and other plant material for mat making and house thatching, and use of the swamp water for domestic and irrigation agriculture. Further monitoring is needed to evaluate the effect of the resource uses on the swamp.